What exactly is the pollen count? That word 'count' caught my attention. How is it counted? Talking about everyday subjects with your class, just for a few minutes, really puts maths into context - and, in this case, gives counting a real-life purpose.
What is the pollen count?
The pollen count measures how many grains of pollen there are in a cubic metre of air. To give children an idea of the size of a cubic metre give 4 children 3 metre sticks each. Ask them to stand in a square each 1m apart, placing a metre stick between them on the ground to show each side of the square. Standing on the 4 corners, the children place another metre stick upright and the third metre stick on the top to form a square directly above the base square. Explain that the cube or box that the 12 metre sticks make is 1 cubic metre. Ask them to imagine 10 tiny grains of pollen in this space, spread out fingers to give an image of 10 - how far apart could they be in the cubic metre? This would be a low pollen count. Now imagine 10 of these groups of 10 grain of pollen. Ask 10 children to put their hands in the cubic metre to give an image of 100 pollen grains, remind them how small pollen grains are compared to their fingers, this would be a high pollen count and would make someone's eyes itch and start them sneezing.
How is pollen counted?
In very simple terms, air is sucked into a trap so that the pollen sticks onto an adhesive tape. The tape is then put on a microscope slide and the pollen is counted. Counting each slide can take an hour and is done manually as there is no automatic method for counting pollen. The BBC has some good information on how pollen is counted.
Try setting up your own pollen count with this activity - using paper and dots.
Give each child a 75 x 25mm piece of paper and explain that this is the same size as a microscope slide. If you have one, show your class a microscope slide.
Write the pollen count chart on the board. Divide your class into three groups – Low, Moderate and High pollen count groups.
Ask each child to choose any number within their pollen count range and write it on one side of their paper, then turn over the paper and draw this exact number of small dots to represent pollen on a microscope slide. Use a pen not a pencil.
Within their group they swap papers and count each others' pollen dots to see how accurately they can count.
Talk about methods to make sure dots are not counted twice or missed:
- using a ruler to move section at a time across the paper;
- using a pencil (so it can be erased) lightly to circle each dot counted;
- dividing the paper into smaller sections and counting each section at a time.
Ask them to swap again and use a different method to count.
Lay the papers, dots up, without looking at the numbers. Ask the group to place them in order, without counting.
Now ask the group to estimate the number of ‘pollen’ dots (again, without counting) on each and write it down.
Turn over the papers and check if they were able to place them in order correctly and how close their guess was to the actual number of dots.
The pollen count measures how many grains of pollen there are in a cubic metre of air. To give children an idea of the size of a cubic metre give 4 children 3 metre sticks each. Ask them to stand in a square each 1m apart, placing a metre stick between them on the ground to show each side of the square. Standing on the 4 corners, the children place another metre stick upright and the third metre stick on the top to form a square directly above the base square. Explain that the cube or box that the 12 metre sticks make is 1 cubic metre. Ask them to imagine 10 tiny grains of pollen in this space, spread out fingers to give an image of 10 - how far apart could they be in the cubic metre? This would be a low pollen count. Now imagine 10 of these groups of 10 grain of pollen. Ask 10 children to put their hands in the cubic metre to give an image of 100 pollen grains, remind them how small pollen grains are compared to their fingers, this would be a high pollen count and would make someone's eyes itch and start them sneezing.
How is pollen counted?
In very simple terms, air is sucked into a trap so that the pollen sticks onto an adhesive tape. The tape is then put on a microscope slide and the pollen is counted. Counting each slide can take an hour and is done manually as there is no automatic method for counting pollen. The BBC has some good information on how pollen is counted.
Try setting up your own pollen count with this activity - using paper and dots.
Counting accurately
Give each child a 75 x 25mm piece of paper and explain that this is the same size as a microscope slide. If you have one, show your class a microscope slide.Write the pollen count chart on the board. Divide your class into three groups – Low, Moderate and High pollen count groups.
Ask each child to choose any number within their pollen count range and write it on one side of their paper, then turn over the paper and draw this exact number of small dots to represent pollen on a microscope slide. Use a pen not a pencil.
Within their group they swap papers and count each others' pollen dots to see how accurately they can count.
Talk about methods to make sure dots are not counted twice or missed:
- using a ruler to move section at a time across the paper;
- using a pencil (so it can be erased) lightly to circle each dot counted;
- dividing the paper into smaller sections and counting each section at a time.
Ask them to swap again and use a different method to count.
Ordering and estimating
Now put children into new groups of 5-6 with at least one person from each pollen count range. Mix up all of their papers and swap them with a different group.Lay the papers, dots up, without looking at the numbers. Ask the group to place them in order, without counting.
Now ask the group to estimate the number of ‘pollen’ dots (again, without counting) on each and write it down.
Turn over the papers and check if they were able to place them in order correctly and how close their guess was to the actual number of dots.
Take a look at real pollen
Prepare a small piece of clear sticky tape pressed lightly onto a dandelion flower (most playing fields have these bright yellow flat flowers at the moment) with another piece of tape on top to seal the pollen.
Children could collect their own – as long as you know they are not hay-fever sufferers!
They will see a fine yellow dust on the sticky tape, but it is very hard to see individual pollen grains without a microscope.
Prepare a small piece of clear sticky tape pressed lightly onto a dandelion flower (most playing fields have these bright yellow flat flowers at the moment) with another piece of tape on top to seal the pollen.
Children could collect their own – as long as you know they are not hay-fever sufferers!
They will see a fine yellow dust on the sticky tape, but it is very hard to see individual pollen grains without a microscope.
| Low | 0 – 30 pollen grains per cubic metre of air |
| Moderate | 30 – 49 pollen grains per cubic metre of air |
| High | 50 – 149 pollen grains per cubic metre of air |
| Very high | over 150 pollen grains per cubic metre of air |
Broadbent Maths Planning Menu - User schools
Counting pollen - Ready to download and print.
Estimating and counting accurately up to 150. A real-life context, good for linking to science, spring or summer and integrating data handling.
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